TECHNICAL PROBLEMS POSED BY THE PRIOR ART
The design of aluminum railcars within the fatigue strength of welded aluminum has been a great challenge to railcar designers. It is highly desirable to use aluminum in areas for product containment, where corrosion protection is needed and to reduce the weight of the railcar, and to use higher strength steel in critical areas for sustaining coupler and vertical lading loads.
Railcars having aluminum body portions comprising side sheets, a top sheet and end sheets made from aluminum are well-known in the art. Some of such railcars utilize an expensive full-length steel center sill underframe arrangement, while others utilize steel/aluminum stub sill underframes. In the latter instance there are two primary approaches. One uses all-aluminum components, including the stub sill. The steel striker and rear draft lugs that accommodate the draft system are usually connected to the aluminum stub sill by means of two-piece fasteners. The other approach employs steel stub sills and bolsters that are fastened to aluminum shear plates and aluminum end stiffeners that are welded to the end sheets.
The prior art aluminum railcar designs are expensive to build and costly to maintain because of the high quality demanded and the use of complicated structural arrangements necessary to avoid high stresses at the welded aluminum areas. Accordingly, there is a need for a simple and more cost-effective aluminum railcar design. More specifically, there is a need for an improved connection arrangement for connecting an all-steel end structure to an aluminum railcar body.